Jerking with a cloud of white smoke

[RenoF250]

My truck has started jerking and making a big cloud of white smoke. When it is doing this the tach jumps all over. CPS was changed ~80k, all other sensors original. No CEL on. It first did it to my wife on a hot day - died three times. I went to check it out and drove home no problems then made many hour long trips without a problem but it has been cooler. Today I was flat towing an FJ40 and it did it going up a hill. Let off the gas tach was fine hit the gas tach jumps and white smoke. Pulled over and nothing exciting so we tried again but it felt like it was missing so I cut the FJ40 loose. On the drive home it ran perfect but it was unloaded.

I picked up a new CPS at Napa, I am going to throw that on let me know where else to look. Frustrating when it only does it under load/hot.

 

[RenoF250]

Pulled the connector on my ICP and it is oily so I will replace that. IPR is clean.

 

[79jasper]

Fuel pressure good?

 

[RenoF250]

When I can test at idle is appears okay. I have an oil pressure sender connected that I can only measure with an ohmmeter with the hood open.

Do you think I am running out of fuel? Pump is original. That would make some sense because it has only been when loaded. I do have a filter pre-pump I can change.

It does not really explain the tach jumping around though. That is what makes me think CPS. I was figuring it was putting out junk which was causing the computer to inject at the wrong times. Can't explain why the tach only jumps when on the throttle though.

It has 204k on it now FWIW.

 

[79jasper]

You may need to clean the fpr screen.

Mine started out like yours, then progressively got worse.
I had previously changed the lift pumped a few months prior, so I changed it again (warranty exchange) thinking it was bad.
Problems got even worse.
Turns out my tank pickups had broken off.

I don't know if that's a problem with the newer trucks also, but something to check.

May change the fuel filter also.

Also check the wiring that runs over the valve cover. It's a high Chaff area.

 

[RenoF250]

You may need to clean the fpr screen.

Mine started out like yours, then progressively got worse.
I had previously changed the lift pumped a few months prior, so I changed it again (warranty exchange) thinking it was bad.
Problems got even worse.
Turns out my tank pickups had broken off.

I don't know if that's a problem with the newer trucks also, but something to check.

May change the fuel filter also.

Also check the wiring that runs over the valve cover. It's a high Chaff area.

What year is yours?

I just did the UVCHs a few hundred miles ago.

I also did the in tank mod so there is no screen in there but there is a filter pre-pump. The truck basically sat all winter - <2k miles in a year. Perhaps the pre-pump filter has algae plugging it.

I hate intermittents, you are never really sure you fixed it.

 

[79jasper]

Mines a 94.

When you say filter pre pump, are you talking about the pump on the frame?
If so, that's the lift pump, and should be the only one you have.

Did you put the new CPS on yet?
May check the wiring to it also.

 

[RenoF250]

Yes, before the pump in the frame that makes the ~60psi for the injectors.

New CPS is on.

I do not see any questionable wiring and tend to think that is not it since that would not be load related. I drove it around a bunch yesterday and it ran perfect.

 

[OLDBULL8]

Pulled the connector on my ICP and it is oily so I will replace that. IPR is clean.

If that ICP is oily it's shot and needs to be changed. It will fluctuate the signal and drive the PCM crazy, that in turn makes the IPR go nuts also, doesn't know what pressure to give the injectors. Sometimes the ICP will work OK, then not. When it starts to act up just pull the connector on the ICP and the PCM will revert to a set IPR pressure. Not good to drive much like that, damage can be done to the injectors, injectors need fuel to cushion the pintles.

 

[Double-S-Diesel]

sounds like injectors, or you loosing fuel pressure.
but when I was loosing fuel pressure I had no smoke, it just died
butn I have seen cps s do wierd stuff

 

[RenoF250]

I am more confused now. Rigged the meter so I could read it while driving and found the pressure is ~55 on startup, then drops to ~30 during normal driving. If I jump on it sometimes it drops to ~25 and others it goes up over 80. Makes no sense. Does the computer control the fuel pressure? I though it was a mechanical regulator. Why would it go up under load?

I think I may get an actual fuel pressure gauge. Right now I just have an oil pressure gauge I calibrated using air pressure. Not very accurate but it knows low from high.

I did get the SES light on the last run but I was running it hard up a hill and I have thrown a low injector pressure code in the past because of my programmer so it is likely that. I do not have my scanner now so I will have to test that later.

 

[79jasper]

What programmer are you running?

Fuel pressure is definitely low.
Does the smoke smell like fuel?

 

[OLDBULL8]

With yourfuel pressure jumping all over, this is what you need.
http://www.dieselorings.com/1999-20...s/7-028-fuel-pressure-relief-rebuild-kit.html

http://www.guzzle7pt3.com/fbowl.php

http://www.dieselorings.com/docs/FuelBowlRebuild.pdf

 

[Double-S-Diesel]

25psi is too low, are you running wvo,
I had trouble with the screens in the tank plugging up

 

[RenoF250]

25psi is too low, are you running wvo,
I had trouble with the screens in the tank plugging up

No regular diesel. I do have a filter pre-pump but the pressure is also going too high so I think I will rebuilding the regulator like Oldbull suggests.

Does low fuel pressure cause a cloud of smoke though? I would think that would make you smoke if you ran out of fuel also.